Please perform the following steps:
> If any screen guard/tampered glass/protection film is available then first disable the fingerprint settings and then remove the screen guard.
> Once screen guard is removed now register the fingerprint again and check the issue.
> If the problem does not get resolved, run the device in Safe mode and reconfigure the fingerprint.
> If the issue still persists, create data backup and reset the device.
> Make sure to use the central fingerprint parts evenly when you register or scan the fingerprint, so that all portions of fingerprint, including the centre and corners have been fully scanned.
>Check for the latest device O/S (Scroll down Notification panel >Settings >Software Update >Download updates manually).
For further assistance, register your concern in Samsung members application (Open Samsung members app >> click on “+“icon > send feedback >> error report / ask question).
Team Samsung Members